Camera shutter



Aug. 23, 1938. G. c. SPICER ET AL CAMERA SHUTTER Filed Sept. 28, 1937 -2Sheets-Sheet 1 INVENTOR.

Grover C. Spice) {2' Ulio 10/176 Q.

4 ATTORNEY.

Aug. 23, 1938. G. c. SPICER ET A1.

CAMERA SHUTTER Filed Sept. 28, 1937 2 Sheets-Sheet 2 IEE.5

Ill 5.4;

Ira-HE ITEM? Patented Aug. 23, 1938 UNITED STATES CAMERA SHUTTER GroverC. Spicer, Lyndhurst, and Otto J. Lange, Fairview, Ohio ApplicationSeptember 28, 1937, Serial No. 166,098

2 Claims.

Our invention relates to a photographic shutter for producing a rounddot in half-tone negatives by the use of a graduated square step.

In half-tone negatives the larger dot, produced by the use of the squarestop, allows a greater depth and eliminates the difiiculties ofoverlapping which is the result of a round stop when it is necessary toget a larger dot for highlights in etching.

A further advantage is that due to the square stop and round dot, theetcher is able to re-etch to a much greater extent, improving the half-tone and making it possible to clean up the plate after regularetching.

These and further advantages may be noted from device disclosed in thefollowing specification and its accompanying illustrations in which:

Fig. 1 is a front elevation of the device with the shutters fullyopened.

Fig. 2 is a side elevation of a camera with the device installed.

Fig. 3 is a front elevation of Fig. 2.

Fig. 4 is a rear elevation of the stationary shutter slide member.

Fig. 5 is a front elevation of the diaphragm cam and shutters in theopen position.

Fig. 6 is a view similar to Fig. 5, but showing the diaphragm camrevolved and the shutters in a partially open position.

Fig. 7 shows the fully closed shutters and revolved cam.

Fig. 8 is a section taken on line 8--8 of Fig. 5.

Again referring to the illustrations, the face of the camera I0 isindicated at H, with a lens scale 35 2 mounted thereon. A split barrelI3 is mounted in the center of the face I of the said camera I0, and hasa rotatable shutter or diaphragm cam l4 mounted therebetween having anaperture IS in the center therethrough and eccentric circular grooves l6and Mia, in the outer face thereof, the outer periphery of the shutteror diaphragm cam being flanged at IT.

A stationary shutter slide member I8 is shouldered at l9 and has acenter aperture 20 there- 45 through, the inner face of said stationaryshutter slide member being grooved at 2| across its face at a 45 degreeangle as shown specifically in Fig. 4.

A pair of shutters 22 and 23 are mounted slidably within the groove 2|of the stationary shutter 50 slide member l8 and between the inner faceof the said member and the outer face of the rotatable diaphragm cam M,the shutters 22 and 23 having square apertures 24 and 25 respectivelyout therethrough at a 45 degree angle to the top and bot- 55 tom edgesthereof, and adjacent the inner end of each shutter the opposed ends ofsaid shutters 22 and 23 have pins 26 and 21 mounted rigidly thereinrespectively. Shutter 23 is slotted at 23a from the inner end to thesquare aperture 25.

The pins 26 and 21 are slidably mounted within the grooves l6 and |6arespectively in the face of the rotatable shutter or diaphragm cam I4 asindicated by the Figs. 5, 6, '7 and 8 specifically, the stationaryshutter slide member |8 being held in position within the flangedperiphery ll of the rotatable shutter or diaphragm cam M by a ring 28secured to the flange ll by screws 29.

A gage or scale indicator 30 is rigidly secured to the flange ll of therotatable shutter or diaphragm cam |4 approximately on the degree lineto the left of the center of the lens tube 3|, the movement of theindicator 30 across the face of the lens scale |2 synchronizing with the(camera setting) scale 32 on the side of the camera It.

In operation, the setting of the lens scale |2 to synchronize with thescale setting 32 is obtained by rotating the rotatable shutter ordiaphragm cam l4 until the indicator 30 reads the same as the scale 32,this rotation causes the pins 26 and 2! in the opposed ends of theshutters 22 and 23 to move in the eccentric grooves l6 and Mia.respectively in the face of the rotatable shutter or diaphragm cam I4,this in turn causes the shutters 22 and 23 to slide in or out within theslot 2| in the face of the stationary shutter slide member l8, the slot23a in the shutter 23 allowing the passage of the end of the saidshutter beyond the pin 26. As the shutters 22 and 23 move inwardly thesquare opening A gets smaller and as they move outwardly the saidopening gets larger as illustrated by Figs. 5, 6, and '7. The stationaryshutter slide member I8 is secured to the split barrel |3 by set screws33 to prevent any movement, as the diaphragm cam I4 is rotated, themaintaining of the 45 degree angle of the slot 2| being necessary forthe proper operation of the shutters.

This operation eliminates all guess work caused by using individualstops and gives a positive control for square stops. It will be notedthat the two sliding parts 22 and 23 are mounted to slide at a 45 degreeangle thus maintaining the four sides of the square opening, parallel tothe sides of the camera which is necessary to make the round dot.

Although we have described a particular embodiment of the presentinvention, it will be apparent that various changes, additions,substitutions can be made therein without departing from the spirit ofthe invention or the scope of the appended claims.

We claim:

1. A camera shutter comprising a fixed plate having a central openingand a diametrical guide groove across its inner face, a pair ofoverlapping blades both slidable radially in said groove, said bladeshaving square openings the edges of which extend at 45 angles to theline of movement of the blades and which openings may be registered moreor less with each other, and a cap plate rotatable on the fixed plateand enclosing the blades, said plate having a pair of intersectingeccentric circular grooves therein, the blades having pins engaged insaid grooves.

2. A camera shutter as in claim 1, one of the blades having alongitudinal slot through which the pin of the other blade extends.

GROVER C. SPICER. OTTO J. LANGE.

